// @ts-nocheck
import { base64ToArrayBuffer } from '../base64ToArrayBuffer'
import { pathToBase64 } from '../pathToBase64'
// import { isBase64 } from '../isBase64';
import { isBase64DataUri } from '../isBase64'
import { isString } from '../isString'

interface File {
  exifdata: any
  iptcdata: any
  xmpdata: any
  src: string
}
class EXIF {
  isXmpEnabled = false
  debug = false
  Tags = {
    // version tags
    0x9000: 'ExifVersion', // EXIF version
    0xa000: 'FlashpixVersion', // Flashpix format version

    // colorspace tags
    0xa001: 'ColorSpace', // Color space information tag

    // image configuration
    0xa002: 'PixelXDimension', // Valid width of meaningful image
    0xa003: 'PixelYDimension', // Valid height of meaningful image
    0x9101: 'ComponentsConfiguration', // Information about channels
    0x9102: 'CompressedBitsPerPixel', // Compressed bits per pixel

    // user information
    0x927c: 'MakerNote', // Any desired information written by the manufacturer
    0x9286: 'UserComment', // Comments by user

    // related file
    0xa004: 'RelatedSoundFile', // Name of related sound file

    // date and time
    0x9003: 'DateTimeOriginal', // Date and time when the original image was generated
    0x9004: 'DateTimeDigitized', // Date and time when the image was stored digitally
    0x9290: 'SubsecTime', // Fractions of seconds for DateTime
    0x9291: 'SubsecTimeOriginal', // Fractions of seconds for DateTimeOriginal
    0x9292: 'SubsecTimeDigitized', // Fractions of seconds for DateTimeDigitized

    // picture-taking conditions
    0x829a: 'ExposureTime', // Exposure time (in seconds)
    0x829d: 'FNumber', // F number
    0x8822: 'ExposureProgram', // Exposure program
    0x8824: 'SpectralSensitivity', // Spectral sensitivity
    0x8827: 'ISOSpeedRatings', // ISO speed rating
    0x8828: 'OECF', // Optoelectric conversion factor
    0x9201: 'ShutterSpeedValue', // Shutter speed
    0x9202: 'ApertureValue', // Lens aperture
    0x9203: 'BrightnessValue', // Value of brightness
    0x9204: 'ExposureBias', // Exposure bias
    0x9205: 'MaxApertureValue', // Smallest F number of lens
    0x9206: 'SubjectDistance', // Distance to subject in meters
    0x9207: 'MeteringMode', // Metering mode
    0x9208: 'LightSource', // Kind of light source
    0x9209: 'Flash', // Flash status
    0x9214: 'SubjectArea', // Location and area of main subject
    0x920a: 'FocalLength', // Focal length of the lens in mm
    0xa20b: 'FlashEnergy', // Strobe energy in BCPS
    0xa20c: 'SpatialFrequencyResponse', //
    0xa20e: 'FocalPlaneXResolution', // Number of pixels in width direction per FocalPlaneResolutionUnit
    0xa20f: 'FocalPlaneYResolution', // Number of pixels in height direction per FocalPlaneResolutionUnit
    0xa210: 'FocalPlaneResolutionUnit', // Unit for measuring FocalPlaneXResolution and FocalPlaneYResolution
    0xa214: 'SubjectLocation', // Location of subject in image
    0xa215: 'ExposureIndex', // Exposure index selected on camera
    0xa217: 'SensingMethod', // Image sensor type
    0xa300: 'FileSource', // Image source (3 == DSC)
    0xa301: 'SceneType', // Scene type (1 == directly photographed)
    0xa302: 'CFAPattern', // Color filter array geometric pattern
    0xa401: 'CustomRendered', // Special processing
    0xa402: 'ExposureMode', // Exposure mode
    0xa403: 'WhiteBalance', // 1 = auto white balance, 2 = manual
    0xa404: 'DigitalZoomRation', // Digital zoom ratio
    0xa405: 'FocalLengthIn35mmFilm', // Equivalent foacl length assuming 35mm film camera (in mm)
    0xa406: 'SceneCaptureType', // Type of scene
    0xa407: 'GainControl', // Degree of overall image gain adjustment
    0xa408: 'Contrast', // Direction of contrast processing applied by camera
    0xa409: 'Saturation', // Direction of saturation processing applied by camera
    0xa40a: 'Sharpness', // Direction of sharpness processing applied by camera
    0xa40b: 'DeviceSettingDescription', //
    0xa40c: 'SubjectDistanceRange', // Distance to subject

    // other tags
    0xa005: 'InteroperabilityIFDPointer',
    0xa420: 'ImageUniqueID', // Identifier assigned uniquely to each image
  }
  TiffTags = {
    0x0100: 'ImageWidth',
    0x0101: 'ImageHeight',
    0x8769: 'ExifIFDPointer',
    0x8825: 'GPSInfoIFDPointer',
    0xa005: 'InteroperabilityIFDPointer',
    0x0102: 'BitsPerSample',
    0x0103: 'Compression',
    0x0106: 'PhotometricInterpretation',
    0x0112: 'Orientation',
    0x0115: 'SamplesPerPixel',
    0x011c: 'PlanarConfiguration',
    0x0212: 'YCbCrSubSampling',
    0x0213: 'YCbCrPositioning',
    0x011a: 'XResolution',
    0x011b: 'YResolution',
    0x0128: 'ResolutionUnit',
    0x0111: 'StripOffsets',
    0x0116: 'RowsPerStrip',
    0x0117: 'StripByteCounts',
    0x0201: 'JPEGInterchangeFormat',
    0x0202: 'JPEGInterchangeFormatLength',
    0x012d: 'TransferFunction',
    0x013e: 'WhitePoint',
    0x013f: 'PrimaryChromaticities',
    0x0211: 'YCbCrCoefficients',
    0x0214: 'ReferenceBlackWhite',
    0x0132: 'DateTime',
    0x010e: 'ImageDescription',
    0x010f: 'Make',
    0x0110: 'Model',
    0x0131: 'Software',
    0x013b: 'Artist',
    0x8298: 'Copyright',
  }
  GPSTags = {
    0x0000: 'GPSVersionID',
    0x0001: 'GPSLatitudeRef',
    0x0002: 'GPSLatitude',
    0x0003: 'GPSLongitudeRef',
    0x0004: 'GPSLongitude',
    0x0005: 'GPSAltitudeRef',
    0x0006: 'GPSAltitude',
    0x0007: 'GPSTimeStamp',
    0x0008: 'GPSSatellites',
    0x0009: 'GPSStatus',
    0x000a: 'GPSMeasureMode',
    0x000b: 'GPSDOP',
    0x000c: 'GPSSpeedRef',
    0x000d: 'GPSSpeed',
    0x000e: 'GPSTrackRef',
    0x000f: 'GPSTrack',
    0x0010: 'GPSImgDirectionRef',
    0x0011: 'GPSImgDirection',
    0x0012: 'GPSMapDatum',
    0x0013: 'GPSDestLatitudeRef',
    0x0014: 'GPSDestLatitude',
    0x0015: 'GPSDestLongitudeRef',
    0x0016: 'GPSDestLongitude',
    0x0017: 'GPSDestBearingRef',
    0x0018: 'GPSDestBearing',
    0x0019: 'GPSDestDistanceRef',
    0x001a: 'GPSDestDistance',
    0x001b: 'GPSProcessingMethod',
    0x001c: 'GPSAreaInformation',
    0x001d: 'GPSDateStamp',
    0x001e: 'GPSDifferential',
  }
  // EXIF 2.3 Spec
  IFD1Tags = {
    0x0100: 'ImageWidth',
    0x0101: 'ImageHeight',
    0x0102: 'BitsPerSample',
    0x0103: 'Compression',
    0x0106: 'PhotometricInterpretation',
    0x0111: 'StripOffsets',
    0x0112: 'Orientation',
    0x0115: 'SamplesPerPixel',
    0x0116: 'RowsPerStrip',
    0x0117: 'StripByteCounts',
    0x011a: 'XResolution',
    0x011b: 'YResolution',
    0x011c: 'PlanarConfiguration',
    0x0128: 'ResolutionUnit',
    0x0201: 'JpegIFOffset', // When image format is JPEG, this value show offset to JPEG data stored.(aka "ThumbnailOffset" or "JPEGInterchangeFormat")
    0x0202: 'JpegIFByteCount', // When image format is JPEG, this value shows data size of JPEG image (aka "ThumbnailLength" or "JPEGInterchangeFormatLength")
    0x0211: 'YCbCrCoefficients',
    0x0212: 'YCbCrSubSampling',
    0x0213: 'YCbCrPositioning',
    0x0214: 'ReferenceBlackWhite',
  }
  StringValues = {
    ExposureProgram: {
      0: 'Not defined',
      1: 'Manual',
      2: 'Normal program',
      3: 'Aperture priority',
      4: 'Shutter priority',
      5: 'Creative program',
      6: 'Action program',
      7: 'Portrait mode',
      8: 'Landscape mode',
    },
    MeteringMode: {
      0: 'Unknown',
      1: 'Average',
      2: 'CenterWeightedAverage',
      3: 'Spot',
      4: 'MultiSpot',
      5: 'Pattern',
      6: 'Partial',
      255: 'Other',
    },
    LightSource: {
      0: 'Unknown',
      1: 'Daylight',
      2: 'Fluorescent',
      3: 'Tungsten (incandescent light)',
      4: 'Flash',
      9: 'Fine weather',
      10: 'Cloudy weather',
      11: 'Shade',
      12: 'Daylight fluorescent (D 5700 - 7100K)',
      13: 'Day white fluorescent (N 4600 - 5400K)',
      14: 'Cool white fluorescent (W 3900 - 4500K)',
      15: 'White fluorescent (WW 3200 - 3700K)',
      17: 'Standard light A',
      18: 'Standard light B',
      19: 'Standard light C',
      20: 'D55',
      21: 'D65',
      22: 'D75',
      23: 'D50',
      24: 'ISO studio tungsten',
      255: 'Other',
    },
    Flash: {
      0x0000: 'Flash did not fire',
      0x0001: 'Flash fired',
      0x0005: 'Strobe return light not detected',
      0x0007: 'Strobe return light detected',
      0x0009: 'Flash fired, compulsory flash mode',
      0x000d: 'Flash fired, compulsory flash mode, return light not detected',
      0x000f: 'Flash fired, compulsory flash mode, return light detected',
      0x0010: 'Flash did not fire, compulsory flash mode',
      0x0018: 'Flash did not fire, auto mode',
      0x0019: 'Flash fired, auto mode',
      0x001d: 'Flash fired, auto mode, return light not detected',
      0x001f: 'Flash fired, auto mode, return light detected',
      0x0020: 'No flash function',
      0x0041: 'Flash fired, red-eye reduction mode',
      0x0045: 'Flash fired, red-eye reduction mode, return light not detected',
      0x0047: 'Flash fired, red-eye reduction mode, return light detected',
      0x0049: 'Flash fired, compulsory flash mode, red-eye reduction mode',
      0x004d:
        'Flash fired, compulsory flash mode, red-eye reduction mode, return light not detected',
      0x004f: 'Flash fired, compulsory flash mode, red-eye reduction mode, return light detected',
      0x0059: 'Flash fired, auto mode, red-eye reduction mode',
      0x005d: 'Flash fired, auto mode, return light not detected, red-eye reduction mode',
      0x005f: 'Flash fired, auto mode, return light detected, red-eye reduction mode',
    },
    SensingMethod: {
      1: 'Not defined',
      2: 'One-chip color area sensor',
      3: 'Two-chip color area sensor',
      4: 'Three-chip color area sensor',
      5: 'Color sequential area sensor',
      7: 'Trilinear sensor',
      8: 'Color sequential linear sensor',
    },
    SceneCaptureType: {
      0: 'Standard',
      1: 'Landscape',
      2: 'Portrait',
      3: 'Night scene',
    },
    SceneType: {
      1: 'Directly photographed',
    },
    CustomRendered: {
      0: 'Normal process',
      1: 'Custom process',
    },
    WhiteBalance: {
      0: 'Auto white balance',
      1: 'Manual white balance',
    },
    GainControl: {
      0: 'None',
      1: 'Low gain up',
      2: 'High gain up',
      3: 'Low gain down',
      4: 'High gain down',
    },
    Contrast: {
      0: 'Normal',
      1: 'Soft',
      2: 'Hard',
    },
    Saturation: {
      0: 'Normal',
      1: 'Low saturation',
      2: 'High saturation',
    },
    Sharpness: {
      0: 'Normal',
      1: 'Soft',
      2: 'Hard',
    },
    SubjectDistanceRange: {
      0: 'Unknown',
      1: 'Macro',
      2: 'Close view',
      3: 'Distant view',
    },
    FileSource: {
      3: 'DSC',
    },

    Components: {
      0: '',
      1: 'Y',
      2: 'Cb',
      3: 'Cr',
      4: 'R',
      5: 'G',
      6: 'B',
    },
  }
  enableXmp() {
    this.isXmpEnabled = true
  }
  disableXmp() {
    this.isXmpEnabled = false
  }
  /**
   * 获取图片数据
   * @param img 图片地址
   * @param callback 回调 返回图片数据
   * */
  getData(img: any, callback: Function) {
    // if (((self.Image && img instanceof self.Image) || (self.HTMLImageElement && img instanceof self.HTMLImageElement)) && !img.complete)
    // 	return false;
    let file: File = {
      src: '',
      exifdata: null,
      iptcdata: null,
      xmpdata: null,
    }
    if (isBase64(img)) {
      file.src = img
    } else if (img.path) {
      file.src = img.path
    } else if (isString(img)) {
      file.src = img
    } else {
      return false
    }

    if (!imageHasData(file)) {
      getImageData(file, callback)
    } else {
      if (callback) {
        callback.call(file)
      }
    }
    return true
  }
  /**
   * 获取图片tag
   * @param img 图片数据
   * @param tag tag 类型
   * */
  getTag(img: File, tag: string) {
    if (!imageHasData(img)) return
    return img.exifdata[tag]
  }
  getIptcTag(img: File, tag: string) {
    if (!imageHasData(img)) return
    return img.iptcdata[tag]
  }
  getAllTags(img: File) {
    if (!imageHasData(img)) return {}
    let a,
      data = img.exifdata,
      tags = {}
    for (a in data) {
      if (data.hasOwnProperty(a)) {
        tags[a] = data[a]
      }
    }
    return tags
  }
  getAllIptcTags(img: File) {
    if (!imageHasData(img)) return {}
    let a,
      data = img.iptcdata,
      tags = {}
    for (a in data) {
      if (data.hasOwnProperty(a)) {
        tags[a] = data[a]
      }
    }
    return tags
  }
  pretty(img: File) {
    if (!imageHasData(img)) return ''
    let a,
      data = img.exifdata,
      strPretty = ''
    for (a in data) {
      if (data.hasOwnProperty(a)) {
        if (typeof data[a] == 'object') {
          if (data[a] instanceof Number) {
            strPretty +=
              a + ' : ' + data[a] + ' [' + data[a].numerator + '/' + data[a].denominator + ']\r\n'
          } else {
            strPretty += a + ' : [' + data[a].length + ' values]\r\n'
          }
        } else {
          strPretty += a + ' : ' + data[a] + '\r\n'
        }
      }
    }
    return strPretty
  }
  readFromBinaryFile(file: ArrayBuffer) {
    return findEXIFinJPEG(file)
  }
}

export const exif = new EXIF()
// export function getData(img, callback) {
// 	const exif = new EXIF()
// 	exif.getData(img, callback)
// }

// export default {getData}
const ExifTags = exif.Tags
const TiffTags = exif.TiffTags
const IFD1Tags = exif.IFD1Tags
const GPSTags = exif.GPSTags
const StringValues = exif.StringValues

function imageHasData(img: File): boolean {
  return !!img.exifdata
}

function objectURLToBlob(url: string, callback: Function) {
  try {
    const http = new XMLHttpRequest()
    http.open('GET', url, true)
    http.responseType = 'blob'
    http.onload = function (e) {
      if (this.status == 200 || this.status === 0) {
        callback(this.response)
      }
    }
    http.send()
  } catch (e) {
    console.warn(e)
  }
}

function getImageData(img: File, callback: Function) {
  function handleBinaryFile(binFile: ArrayBuffer) {
    const data = findEXIFinJPEG(binFile)
    img.exifdata = data ?? {}
    const iptcdata = findIPTCinJPEG(binFile)
    img.iptcdata = iptcdata ?? {}
    if (exif.isXmpEnabled) {
      const xmpdata = findXMPinJPEG(binFile)
      img.xmpdata = xmpdata ?? {}
    }
    if (callback) {
      callback.call(img)
    }
  }

  if (img.src) {
    if (/^data\:/i.test(img.src)) {
      // Data URI
      // var arrayBuffer = base64ToArrayBuffer(img.src);
      handleBinaryFile(base64ToArrayBuffer(img.src))
    } else if (/^blob\:/i.test(img.src) && typeof FileReader !== 'undefined') {
      // Object URL
      var fileReader = new FileReader()
      fileReader.onload = function (e) {
        handleBinaryFile(e.target.result)
      }
      objectURLToBlob(img.src, function (blob: Blob) {
        fileReader.readAsArrayBuffer(blob)
      })
    } else if (typeof XMLHttpRequest !== 'undefined') {
      var http = new XMLHttpRequest()
      http.onload = function () {
        if (this.status == 200 || this.status === 0) {
          handleBinaryFile(http.response)
        } else {
          throw 'Could not load image'
        }
        http = null
      }
      http.open('GET', img.src, true)
      http.responseType = 'arraybuffer'
      http.send(null)
    } else {
      pathToBase64(img.src).then((res) => {
        handleBinaryFile(base64ToArrayBuffer(res))
      })
    }
  } else if (
    typeof FileReader !== 'undefined' &&
    self.FileReader &&
    (img instanceof self.Blob || img instanceof self.File)
  ) {
    var fileReader = new FileReader()
    fileReader.onload = function (e: any) {
      if (exif.debug) console.log('Got file of length ' + e.target.result.byteLength)
      handleBinaryFile(e.target.result)
    }

    fileReader.readAsArrayBuffer(img)
  }
}

function findEXIFinJPEG(file: ArrayBuffer) {
  const dataView = new DataView(file)

  if (exif.debug) console.log('Got file of length ' + file.byteLength)
  if (dataView.getUint8(0) != 0xff || dataView.getUint8(1) != 0xd8) {
    if (exif.debug) console.log('Not a valid JPEG')
    return false // not a valid jpeg
  }

  let offset = 2,
    length = file.byteLength,
    marker

  while (offset < length) {
    if (dataView.getUint8(offset) != 0xff) {
      if (exif.debug)
        console.log(
          'Not a valid marker at offset ' + offset + ', found: ' + dataView.getUint8(offset),
        )
      return false // not a valid marker, something is wrong
    }

    marker = dataView.getUint8(offset + 1)
    if (exif.debug) console.log(marker)

    // we could implement handling for other markers here,
    // but we're only looking for 0xFFE1 for EXIF data

    if (marker == 225) {
      if (exif.debug) console.log('Found 0xFFE1 marker')

      return readEXIFData(dataView, offset + 4, dataView.getUint16(offset + 2) - 2)

      // offset += 2 + file.getShortAt(offset+2, true);
    } else {
      offset += 2 + dataView.getUint16(offset + 2)
    }
  }
}

function findIPTCinJPEG(file: ArrayBuffer) {
  const dataView = new DataView(file)

  if (exif.debug) console.log('Got file of length ' + file.byteLength)
  if (dataView.getUint8(0) != 0xff || dataView.getUint8(1) != 0xd8) {
    if (exif.debug) console.log('Not a valid JPEG')
    return false // not a valid jpeg
  }

  let offset = 2,
    length = file.byteLength

  const isFieldSegmentStart = function (dataView, offset: number) {
    return (
      dataView.getUint8(offset) === 0x38 &&
      dataView.getUint8(offset + 1) === 0x42 &&
      dataView.getUint8(offset + 2) === 0x49 &&
      dataView.getUint8(offset + 3) === 0x4d &&
      dataView.getUint8(offset + 4) === 0x04 &&
      dataView.getUint8(offset + 5) === 0x04
    )
  }

  while (offset < length) {
    if (isFieldSegmentStart(dataView, offset)) {
      // Get the length of the name header (which is padded to an even number of bytes)
      var nameHeaderLength = dataView.getUint8(offset + 7)
      if (nameHeaderLength % 2 !== 0) nameHeaderLength += 1
      // Check for pre photoshop 6 format
      if (nameHeaderLength === 0) {
        // Always 4
        nameHeaderLength = 4
      }

      var startOffset = offset + 8 + nameHeaderLength
      var sectionLength = dataView.getUint16(offset + 6 + nameHeaderLength)

      return readIPTCData(file, startOffset, sectionLength)

      break
    }

    // Not the marker, continue searching
    offset++
  }
}

const IptcFieldMap = {
  0x78: 'caption',
  0x6e: 'credit',
  0x19: 'keywords',
  0x37: 'dateCreated',
  0x50: 'byline',
  0x55: 'bylineTitle',
  0x7a: 'captionWriter',
  0x69: 'headline',
  0x74: 'copyright',
  0x0f: 'category',
}

function readIPTCData(file: ArrayBuffer, startOffset: number, sectionLength: number) {
  const dataView = new DataView(file)
  let data = {}
  let fieldValue, fieldName, dataSize, segmentType, segmentSize
  let segmentStartPos = startOffset
  while (segmentStartPos < startOffset + sectionLength) {
    if (
      dataView.getUint8(segmentStartPos) === 0x1c &&
      dataView.getUint8(segmentStartPos + 1) === 0x02
    ) {
      segmentType = dataView.getUint8(segmentStartPos + 2)
      if (segmentType in IptcFieldMap) {
        dataSize = dataView.getInt16(segmentStartPos + 3)
        segmentSize = dataSize + 5
        fieldName = IptcFieldMap[segmentType]
        fieldValue = getStringFromDB(dataView, segmentStartPos + 5, dataSize)
        // Check if we already stored a value with this name
        if (data.hasOwnProperty(fieldName)) {
          // Value already stored with this name, create multivalue field
          if (data[fieldName] instanceof Array) {
            data[fieldName].push(fieldValue)
          } else {
            data[fieldName] = [data[fieldName], fieldValue]
          }
        } else {
          data[fieldName] = fieldValue
        }
      }
    }
    segmentStartPos++
  }
  return data
}

function readTags(
  file: DataView,
  tiffStart: number,
  dirStart: number,
  strings: any[],
  bigEnd: number,
) {
  let entries = file.getUint16(dirStart, !bigEnd),
    tags = {},
    entryOffset,
    tag

  for (let i = 0; i < entries; i++) {
    entryOffset = dirStart + i * 12 + 2
    tag = strings[file.getUint16(entryOffset, !bigEnd)]
    if (!tag && exif.debug) console.log('Unknown tag: ' + file.getUint16(entryOffset, !bigEnd))
    tags[tag] = readTagValue(file, entryOffset, tiffStart, dirStart, bigEnd)
  }
  return tags
}

function readTagValue(
  file: DataView,
  entryOffset: number,
  tiffStart: number,
  dirStart: number,
  bigEnd: number,
) {
  let type = file.getUint16(entryOffset + 2, !bigEnd),
    numValues = file.getUint32(entryOffset + 4, !bigEnd),
    valueOffset = file.getUint32(entryOffset + 8, !bigEnd) + tiffStart,
    offset,
    vals,
    val,
    n,
    numerator,
    denominator

  switch (type) {
    case 1: // byte, 8-bit unsigned int
    case 7: // undefined, 8-bit byte, value depending on field
      if (numValues == 1) {
        return file.getUint8(entryOffset + 8, !bigEnd)
      } else {
        offset = numValues > 4 ? valueOffset : entryOffset + 8
        vals = []
        for (n = 0; n < numValues; n++) {
          vals[n] = file.getUint8(offset + n)
        }
        return vals
      }

    case 2: // ascii, 8-bit byte
      offset = numValues > 4 ? valueOffset : entryOffset + 8
      return getStringFromDB(file, offset, numValues - 1)

    case 3: // short, 16 bit int
      if (numValues == 1) {
        return file.getUint16(entryOffset + 8, !bigEnd)
      } else {
        offset = numValues > 2 ? valueOffset : entryOffset + 8
        vals = []
        for (n = 0; n < numValues; n++) {
          vals[n] = file.getUint16(offset + 2 * n, !bigEnd)
        }
        return vals
      }

    case 4: // long, 32 bit int
      if (numValues == 1) {
        return file.getUint32(entryOffset + 8, !bigEnd)
      } else {
        vals = []
        for (n = 0; n < numValues; n++) {
          vals[n] = file.getUint32(valueOffset + 4 * n, !bigEnd)
        }
        return vals
      }

    case 5: // rational = two long values, first is numerator, second is denominator
      if (numValues == 1) {
        numerator = file.getUint32(valueOffset, !bigEnd)
        denominator = file.getUint32(valueOffset + 4, !bigEnd)
        val = new Number(numerator / denominator)
        val.numerator = numerator
        val.denominator = denominator
        return val
      } else {
        vals = []
        for (n = 0; n < numValues; n++) {
          numerator = file.getUint32(valueOffset + 8 * n, !bigEnd)
          denominator = file.getUint32(valueOffset + 4 + 8 * n, !bigEnd)
          vals[n] = new Number(numerator / denominator)
          vals[n].numerator = numerator
          vals[n].denominator = denominator
        }
        return vals
      }

    case 9: // slong, 32 bit signed int
      if (numValues == 1) {
        return file.getInt32(entryOffset + 8, !bigEnd)
      } else {
        vals = []
        for (n = 0; n < numValues; n++) {
          vals[n] = file.getInt32(valueOffset + 4 * n, !bigEnd)
        }
        return vals
      }

    case 10: // signed rational, two slongs, first is numerator, second is denominator
      if (numValues == 1) {
        return file.getInt32(valueOffset, !bigEnd) / file.getInt32(valueOffset + 4, !bigEnd)
      } else {
        vals = []
        for (n = 0; n < numValues; n++) {
          vals[n] =
            file.getInt32(valueOffset + 8 * n, !bigEnd) /
            file.getInt32(valueOffset + 4 + 8 * n, !bigEnd)
        }
        return vals
      }
  }
}
/**
 * Given an IFD (Image File Directory) start offset
 * returns an offset to next IFD or 0 if it's the last IFD.
 */
function getNextIFDOffset(dataView: DataView, dirStart: number, bigEnd: number) {
  //the first 2bytes means the number of directory entries contains in this IFD
  var entries = dataView.getUint16(dirStart, !bigEnd)

  // After last directory entry, there is a 4bytes of data,
  // it means an offset to next IFD.
  // If its value is '0x00000000', it means this is the last IFD and there is no linked IFD.

  return dataView.getUint32(dirStart + 2 + entries * 12, !bigEnd) // each entry is 12 bytes long
}

function readThumbnailImage(
  dataView: DataView,
  tiffStart: number,
  firstIFDOffset: number,
  bigEnd: number,
) {
  // get the IFD1 offset
  const IFD1OffsetPointer = getNextIFDOffset(dataView, tiffStart + firstIFDOffset, bigEnd)

  if (!IFD1OffsetPointer) {
    // console.log('******** IFD1Offset is empty, image thumb not found ********');
    return {}
  } else if (IFD1OffsetPointer > dataView.byteLength) {
    // this should not happen
    // console.log('******** IFD1Offset is outside the bounds of the DataView ********');
    return {}
  }
  // console.log('*******  thumbnail IFD offset (IFD1) is: %s', IFD1OffsetPointer);

  let thumbTags: any = readTags(
    dataView,
    tiffStart,
    tiffStart + IFD1OffsetPointer,
    IFD1Tags,
    bigEnd,
  )

  // EXIF 2.3 specification for JPEG format thumbnail

  // If the value of Compression(0x0103) Tag in IFD1 is '6', thumbnail image format is JPEG.
  // Most of Exif image uses JPEG format for thumbnail. In that case, you can get offset of thumbnail
  // by JpegIFOffset(0x0201) Tag in IFD1, size of thumbnail by JpegIFByteCount(0x0202) Tag.
  // Data format is ordinary JPEG format, starts from 0xFFD8 and ends by 0xFFD9. It seems that
  // JPEG format and 160x120pixels of size are recommended thumbnail format for Exif2.1 or later.

  if (thumbTags['Compression'] && typeof Blob !== 'undefined') {
    // console.log('Thumbnail image found!');

    switch (thumbTags['Compression']) {
      case 6:
        // console.log('Thumbnail image format is JPEG');
        if (thumbTags.JpegIFOffset && thumbTags.JpegIFByteCount) {
          // extract the thumbnail
          var tOffset = tiffStart + thumbTags.JpegIFOffset
          var tLength = thumbTags.JpegIFByteCount
          thumbTags['blob'] = new Blob([new Uint8Array(dataView.buffer, tOffset, tLength)], {
            type: 'image/jpeg',
          })
        }
        break

      case 1:
        console.log('Thumbnail image format is TIFF, which is not implemented.')
        break
      default:
        console.log("Unknown thumbnail image format '%s'", thumbTags['Compression'])
    }
  } else if (thumbTags['PhotometricInterpretation'] == 2) {
    console.log('Thumbnail image format is RGB, which is not implemented.')
  }
  return thumbTags
}

function getStringFromDB(buffer: DataView, start: number, length: number) {
  let outstr = ''
  for (let n = start; n < start + length; n++) {
    outstr += String.fromCharCode(buffer.getUint8(n))
  }
  return outstr
}

function readEXIFData(file: DataView, start: number) {
  if (getStringFromDB(file, start, 4) != 'Exif') {
    if (exif.debug) console.log('Not valid EXIF data! ' + getStringFromDB(file, start, 4))
    return false
  }

  let bigEnd,
    tags,
    tag,
    exifData,
    gpsData,
    tiffOffset = start + 6

  // test for TIFF validity and endianness
  if (file.getUint16(tiffOffset) == 0x4949) {
    bigEnd = false
  } else if (file.getUint16(tiffOffset) == 0x4d4d) {
    bigEnd = true
  } else {
    if (exif.debug) console.log('Not valid TIFF data! (no 0x4949 or 0x4D4D)')
    return false
  }

  if (file.getUint16(tiffOffset + 2, !bigEnd) != 0x002a) {
    if (exif.debug) console.log('Not valid TIFF data! (no 0x002A)')
    return false
  }

  const firstIFDOffset = file.getUint32(tiffOffset + 4, !bigEnd)

  if (firstIFDOffset < 0x00000008) {
    if (exif.debug)
      console.log(
        'Not valid TIFF data! (First offset less than 8)',
        file.getUint32(tiffOffset + 4, !bigEnd),
      )
    return false
  }

  tags = readTags(file, tiffOffset, tiffOffset + firstIFDOffset, TiffTags, bigEnd)

  if (tags.ExifIFDPointer) {
    exifData = readTags(file, tiffOffset, tiffOffset + tags.ExifIFDPointer, ExifTags, bigEnd)
    for (tag in exifData) {
      switch (tag) {
        case 'LightSource':
        case 'Flash':
        case 'MeteringMode':
        case 'ExposureProgram':
        case 'SensingMethod':
        case 'SceneCaptureType':
        case 'SceneType':
        case 'CustomRendered':
        case 'WhiteBalance':
        case 'GainControl':
        case 'Contrast':
        case 'Saturation':
        case 'Sharpness':
        case 'SubjectDistanceRange':
        case 'FileSource':
          exifData[tag] = StringValues[tag][exifData[tag]]
          break

        case 'ExifVersion':
        case 'FlashpixVersion':
          exifData[tag] = String.fromCharCode(
            exifData[tag][0],
            exifData[tag][1],
            exifData[tag][2],
            exifData[tag][3],
          )
          break

        case 'ComponentsConfiguration':
          exifData[tag] =
            StringValues.Components[exifData[tag][0]] +
            StringValues.Components[exifData[tag][1]] +
            StringValues.Components[exifData[tag][2]] +
            StringValues.Components[exifData[tag][3]]
          break
      }
      tags[tag] = exifData[tag]
    }
  }

  if (tags.GPSInfoIFDPointer) {
    gpsData = readTags(file, tiffOffset, tiffOffset + tags.GPSInfoIFDPointer, GPSTags, bigEnd)
    for (tag in gpsData) {
      switch (tag) {
        case 'GPSVersionID':
          gpsData[tag] =
            gpsData[tag][0] + '.' + gpsData[tag][1] + '.' + gpsData[tag][2] + '.' + gpsData[tag][3]
          break
      }
      tags[tag] = gpsData[tag]
    }
  }

  // extract thumbnail
  tags['thumbnail'] = readThumbnailImage(file, tiffOffset, firstIFDOffset, bigEnd)

  return tags
}

function findXMPinJPEG(file: ArrayBuffer) {
  if (!('DOMParser' in self)) {
    // console.warn('XML parsing not supported without DOMParser');
    return
  }
  const dataView = new DataView(file)

  if (exif.debug) console.log('Got file of length ' + file.byteLength)
  if (dataView.getUint8(0) != 0xff || dataView.getUint8(1) != 0xd8) {
    if (exif.debug) console.log('Not a valid JPEG')
    return false // not a valid jpeg
  }

  let offset = 2,
    length = file.byteLength,
    dom = new DOMParser()

  while (offset < length - 4) {
    if (getStringFromDB(dataView, offset, 4) == 'http') {
      const startOffset = offset - 1
      const sectionLength = dataView.getUint16(offset - 2) - 1
      let xmpString = getStringFromDB(dataView, startOffset, sectionLength)
      const xmpEndIndex = xmpString.indexOf('xmpmeta>') + 8
      xmpString = xmpString.substring(xmpString.indexOf('<x:xmpmeta'), xmpEndIndex)

      const indexOfXmp = xmpString.indexOf('x:xmpmeta') + 10
      //Many custom written programs embed xmp/xml without any namespace. Following are some of them.
      //Without these namespaces, XML is thought to be invalid by parsers
      xmpString =
        xmpString.slice(0, indexOfXmp) +
        'xmlns:Iptc4xmpCore="http://iptc.org/std/Iptc4xmpCore/1.0/xmlns/" ' +
        'xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" ' +
        'xmlns:tiff="http://ns.adobe.com/tiff/1.0/" ' +
        'xmlns:plus="http://schemas.android.com/apk/lib/com.google.android.gms.plus" ' +
        'xmlns:ext="http://www.gettyimages.com/xsltExtension/1.0" ' +
        'xmlns:exif="http://ns.adobe.com/exif/1.0/" ' +
        'xmlns:stEvt="http://ns.adobe.com/xap/1.0/sType/ResourceEvent#" ' +
        'xmlns:stRef="http://ns.adobe.com/xap/1.0/sType/ResourceRef#" ' +
        'xmlns:crs="http://ns.adobe.com/camera-raw-settings/1.0/" ' +
        'xmlns:xapGImg="http://ns.adobe.com/xap/1.0/g/img/" ' +
        'xmlns:Iptc4xmpExt="http://iptc.org/std/Iptc4xmpExt/2008-02-29/" ' +
        xmpString.slice(indexOfXmp)

      var domDocument = dom.parseFromString(xmpString, 'text/xml')
      return xml2Object(domDocument)
    } else {
      offset++
    }
  }
}

function xml2json(xml: any) {
  var json = {}

  if (xml.nodeType == 1) {
    // element node
    if (xml.attributes.length > 0) {
      json['@attributes'] = {}
      for (var j = 0; j < xml.attributes.length; j++) {
        var attribute = xml.attributes.item(j)
        json['@attributes'][attribute.nodeName] = attribute.nodeValue
      }
    }
  } else if (xml.nodeType == 3) {
    // text node
    return xml.nodeValue
  }

  // deal with children
  if (xml.hasChildNodes()) {
    for (var i = 0; i < xml.childNodes.length; i++) {
      var child = xml.childNodes.item(i)
      var nodeName = child.nodeName
      if (json[nodeName] == null) {
        json[nodeName] = xml2json(child)
      } else {
        if (json[nodeName].push == null) {
          var old = json[nodeName]
          json[nodeName] = []
          json[nodeName].push(old)
        }
        json[nodeName].push(xml2json(child))
      }
    }
  }

  return json
}

function xml2Object(xml: any) {
  try {
    var obj = {}
    if (xml.children.length > 0) {
      for (var i = 0; i < xml.children.length; i++) {
        var item = xml.children.item(i)
        var attributes = item.attributes
        for (var idx in attributes) {
          var itemAtt = attributes[idx]
          var dataKey = itemAtt.nodeName
          var dataValue = itemAtt.nodeValue

          if (dataKey !== undefined) {
            obj[dataKey] = dataValue
          }
        }
        var nodeName = item.nodeName

        if (typeof obj[nodeName] == 'undefined') {
          obj[nodeName] = xml2json(item)
        } else {
          if (typeof obj[nodeName].push == 'undefined') {
            var old = obj[nodeName]

            obj[nodeName] = []
            obj[nodeName].push(old)
          }
          obj[nodeName].push(xml2json(item))
        }
      }
    } else {
      obj = xml.textContent
    }
    return obj
  } catch (e) {
    console.log(e.message)
  }
}
